LT1-LT4 Modifications 1993-97 Gen II Small Block V8

power loss

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Old 02-25-2017, 02:57 PM
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Originally Posted by hrcslam
Yes. But it's possible. Although it's a lot faster with the wide bands.
it goes out the window if you have a cam in the car with any overlap or long tubes.
Old 02-25-2017, 03:11 PM
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Originally Posted by ddnspider
it goes out the window if you have a cam in the car with any overlap or long tubes.
Worked alright for me.....
Old 02-25-2017, 04:17 PM
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Originally Posted by hrcslam
Worked alright for me.....
than you don't have a cam with any significant amount of overlap or have unicorn headers. It's a limitation of how oxygen sensors function so I guess you just know something nobody else does, congrats. Meanwhile instead of guessing I'll actually know what my air fuel is instead of a weighted average like a stock o2.
Old 02-25-2017, 05:41 PM
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Originally Posted by ddnspider
than you don't have a cam with any significant amount of overlap or have unicorn headers. It's a limitation of how oxygen sensors function so I guess you just know something nobody else does, congrats. Meanwhile instead of guessing I'll actually know what my air fuel is instead of a weighted average like a stock o2.
My build specs begs to differ.....

Again, a wideband is better and faster at tuning. But just like a compass vs GPS you can still get to your destination, if you know what you're doing. It just takes longer.

You can say what you want about theory of operation. I understand all that. Difference is that I've actually tuned my car with narrow band o2s. Because I understand theory of operation, I also know that is 100% possible to tune using narrow band o2s on cammed up engines with headers.

Apparently scavenging and reverb makes narrow band o2s useless.....

Last edited by hrcslam; 02-25-2017 at 05:48 PM.
Old 02-25-2017, 05:45 PM
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Originally Posted by ddnspider
than you don't have a cam with any significant amount of overlap or have unicorn headers. It's a limitation of how oxygen sensors function so I guess you just know something nobody else does, congrats. Meanwhile instead of guessing I'll actually know what my air fuel is instead of a weighted average like a stock o2.
from what im seeing the guy cant afford a wideband right now and theyre trying to troubleshoot other ways to track down the issue. im by far no expert and not trying to give any weight to either argument but its frustrating for us who are trying to learn who read these threads and cant afford the wideband either. hints/tips/tricks are always appreciated
Old 02-25-2017, 06:04 PM
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Originally Posted by CFLFORMULA93
from what im seeing the guy cant afford a wideband right now and theyre trying to troubleshoot other ways to track down the issue. im by far no expert and not trying to give any weight to either argument but its frustrating for us who are trying to learn who read these threads and cant afford the wideband either. hints/tips/tricks are always appreciated
There's really nothing different to learn when tuning with narrow band than wide band. Wide band O2's have more accurate resolution over a wider range of AFR than narrow band. That's it. But, that makes tuning far faster and easier. Especially when you can't emulate and loading tunes take 5-10 minutes per load.

When tuning with narrow bands you have to let the BLM's settle and make adjustment based off of those in the datalog, but you can only walk it in slowly (you'd want to use the most recent data on the BLM's for adjusting the tune. for example if cell 10 says 128 at the beginning of a data log, but at the end of the log it shows 135 you'd want to adjust that BLM cell 105% in the tune. In reality you'd probably only do 102.5% and log again). You can't see a narrow band showing 108 BLM and assume you can remove 15% of your fueling, because at that mV the narrow band is very inaccurate. You'd want to instead take out half of that and data log again. Rinse and repeat.

If using a wide band you can see AFR at 1.15 Lambda (BLM's would read 108 here) and know you can pull 15% fueling safely, although you'd still not want to pull all of it. Also with a wide band, you'll see the AFR instantly. You don't have to wait for the BLMs to adjust and settle in the data log. This is especially helpful on a dyno, or on a datalogger with the wide bands wired directly to it.

When is comes to headers, you'd want to adjust the voltage delay (this tells the computer that the O2 sensor is further from the heads than stock), so the ECM can more accurately adjust BLM's to the correct BLM Cell.

With bigger cams, you'd want to adjust the O2 mV target at lower RPM's to account for the overlap and reverb.

Last edited by hrcslam; 03-01-2017 at 11:58 PM.
Old 02-25-2017, 07:01 PM
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Well drove to work today with a fuel pressure gauge hanging out of the hood. Initial pressure was 42 where I set it with the engine off. Start the engine and pressure drops to the low 30's. Lower than I'm used to but runs well. Open up the taps as its warming and pulls hard with good pressure near 40psi as the vacuum fades. 20 Minutes in I am watching the pressure waver a little in the low 30'2 as I cruse, then I down shift to 3rd floor it and watch the pressure jump to 40 for a second and as the rpm's increase the pressure plummets to 0. As soon as I let off the pressure is back but wont break 30psi now. Pull in to the gas station top off and remove the vacuum line. car is locked at 42psi even through a hard pull right after I start the car. Drive the last 15 minutes to work and back to the same problem, hard pull and the pressure dives to 0. So we have confirmed it is a flow issue. Because it is time sensitive I am really leaning to a fuel pump. What do you guys think?
Old 02-25-2017, 08:13 PM
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Originally Posted by space387
Well drove to work today with a fuel pressure gauge hanging out of the hood. Initial pressure was 42 where I set it with the engine off. Start the engine and pressure drops to the low 30's. Lower than I'm used to but runs well. Open up the taps as its warming and pulls hard with good pressure near 40psi as the vacuum fades. 20 Minutes in I am watching the pressure waver a little in the low 30'2 as I cruse, then I down shift to 3rd floor it and watch the pressure jump to 40 for a second and as the rpm's increase the pressure plummets to 0. As soon as I let off the pressure is back but wont break 30psi now. Pull in to the gas station top off and remove the vacuum line. car is locked at 42psi even through a hard pull right after I start the car. Drive the last 15 minutes to work and back to the same problem, hard pull and the pressure dives to 0. So we have confirmed it is a flow issue. Because it is time sensitive I am really leaning to a fuel pump. What do you guys think?
I agree, fuel pump.
Old 02-25-2017, 08:25 PM
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Originally Posted by hrcslam
There's really nothing different to learn when tuning with narrow band than wide band. Wide band O2's have more accurate resolution over a wider range of AFR than narrow band. That's it. But, that makes tuning far faster and easier. Especially when you can't emulate and loading tunes take 5-10 minutes per load.

When tuning with narrow bands you have to let the BLM's settle and make adjustment based off of those in the datalog, but you can only walk it in slowly (you'd want to use the most recent data on the BLM's for adjusting the tune. for example if cell 10 says 128 at the beging of a data log, but at the end of the log it shows 135 you'd want to adjust that BLM cell 1.05% in the tune. In reality you'd probably only do 1.025% and log again). You can't see a narrow band showing 108 BLM and assume you can remove 15% of your fueling, because at that mV the narrow band is very inaccurate. You'd want to instead take out half of that and data log again. Rinse and repeat.

If using a wide band you can see AFR at 1.15 Lambda (BLM's would read 108 here) and know you can pull 15% fueling safely, although you'd still not want to pull all of it. Also with a wide band, you'll see the AFR instantly. You don't have to wait for the BLMs to adjust and settle in the data log. This is especially helpful on a dyno, or on a datalogger with the wide bands wired directly to it.

When is comes to headers, you'd want to adjust the voltage delay (this tells the computer that the O2 sensor is further from the heads than stock), so the ECM can more accurately adjust BLM's to the correct BLM Cell.

With bigger cams, you'd want to adjust the O2 mV target at lower RPM's to account for the overlap and reverb.
TLDR....I skimmed it and literally am amazed you're trying to argue that narrowband o2 tuning is just as good as wideband tuning just takes longer. Why bother with creating wideband sensors if narrowbands are just as good? I've tuned huge overlap NA motors that drove like stock and 900hp boosted setups so I think I'll stick to what professionals use instead of backyard hacks. Is this what the LT1 section is always like? My fault for being curious of the thread title. Good luck to the OP, get that fuel pump swapped and hopefully it solves your issue.
Old 02-25-2017, 08:39 PM
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Originally Posted by ddnspider
TLDR....I skimmed it and literally am amazed you're trying to argue that narrowband o2 tuning is just as good as wideband tuning just takes longer. Why bother with creating wideband sensors if narrowbands are just as good? I've tuned huge overlap NA motors that drove like stock and 900hp boosted setups so I think I'll stick to what professionals use instead of backyard hacks. Is this what the LT1 section is always like? My fault for being curious of the thread title. Good luck to the OP, get that fuel pump swapped and hopefully it solves your issue.
You're oblivious if you think that 450mV is any different if it comes from a wide band or a narrow band.

I never said the wide band was worse, in any way. But if you think it's impossible to do it with narrow bands, your skills are lacking. Because I have. My build (see sig) can grab 45mph in ANY gear (all 6) with 3.42s smoothly. You can't say it's not possible when it has actually happened.

It's truly sad you coming in here thinking you're better than everyone else only to learn your skills aren't very impressive at all. You have not provided any helpful posts at all. All of your comments are about how someone is doing something wrong. Yet the issue was found and with out your precious wide band to boot.....
Old 02-25-2017, 08:45 PM
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Originally Posted by hrcslam
You're oblivious if you think that 450mV is any different if it comes from a wide band or a narrow band.

I never said the wide band was worse, in any way. But if you think it's impossible to do it with narrow bands, your skills are lacking. Because I have. My build (see sig) can grab 45mph in ANY gear (all 6) with 3.42s smoothly. You can't say it's not possible when it has actually happened.

It's truly sad you coming in here thinking you're better than everyone else only to learn your skills aren't very impressive at all. You have not provided any helpful posts at all. All of your comments are about how someone is doing something wrong. Yet the issue was found and with out your precious wide band to boot.....
Hey jackass, I've tuned with narrow bands before.....when I was an amateur and didn't know jack but thought I did. You're not arguing the wide and is worse, you're arguing a narrowband is just as good, which is hilarious and shows how little you know. I never said it's impossible to find a problem without a wideband but the OP sure spent a ton of time searching that a simple drive with a wideband or a fuel pressure gauge would have found immediately. Youre time isnt free. Im done in here, ignorant idiot.
Old 02-25-2017, 08:53 PM
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Originally Posted by ddnspider
Hey jackass, I've tuned with narrow bands before.....when I was an amateur and didn't know jack but thought I did. You're not arguing the wide and is worse, you're arguing a narrowband is just as good, which is hilarious and shows how little you know. I never said it's impossible to find a problem without a wideband but the OP sure spent a ton of time searching that a simple drive with a wideband or a fuel pressure gauge would have found immediately. Youre time isnt free. Im done in here, ignorant idiot.
Show me once where I said a narrow band is just as good... I'll wait. Name calling now? Lol.

Saying it's possible and saying they are equal are two completely different things. Just because you lack the skill to fine tune the ECM with narrowbands doesn't make it impossible.

BTW, having a wideband for this issue would help absolutely nothing for troubleshooting over a narrowband. Genius.
Old 02-25-2017, 08:59 PM
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What do you think happens when your fuel pressure drops? Does your air fuel stay the same or change? And you have multiple misleading statements in your posts that imply tuning with a narrowband is just as good. No no you're right, keep doing what you're doing, enjoy, best of luck to you. Enjoy.
Old 02-25-2017, 09:28 PM
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Originally Posted by ddnspider
What do you think happens when your fuel pressure drops? Does your air fuel stay the same or change? And you have multiple misleading statements in your posts that imply tuning with a narrowband is just as good. No no you're right, keep doing what you're doing, enjoy, best of luck to you. Enjoy.
Would you like to get into the discussion of fluid dynamics? Because your question leads to that in relation to thermal dynamics. In any case the same results will be shown by either type of sensor. That leaves your argument moot.

There's nothing misleading about what I said. I was pretty clear the wide band is a very good tool (better than a narrow band) for tuning. I was also clear that you can use the narrow band if you actually know what you're doing, and it can be very effective, but takes a lot longer.

For his purpose of troubleshooting, a wide band is not necessary at all. Maybe you should stick to the LS.....
Old 02-25-2017, 09:31 PM
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just going to toss this out, both will show rich, Stoichiometric and lean. one is just a much much more accurate calculation of how much. Your right I would have saved a lot of time if I went strait to fuel, BUT, initial fuel pressure when the pump has rested is 43psi as I have set in the FPR. The narrow bands displayed the engine gets leaner at WOT as time progresses. In my first few attempts I was not seeing this. It took more time for the problem to get worse so it manifest more often so I could see the issue. The narrow bands are being used for their intended purpose, as a tool for the ecm to maintain Stoichiometric mixture and for the person working on it to troubleshoot major issues.

To the side topic you guys have rambled on, you CAN tune with narrow bands, I did with megasquirt 1 on my 3.4L, but the widebands turned 2 weeks work into 2 hours. I am no stranger to engine dynamics and theory.

Due to being unfamiliar with the engine and diagnostic program I could not see the burning tree in the forest fire. Thank you both for your input and help and rest assure when I want more power than I have I will get a WB and a dyno tune

Where is the emoticon for runaway thread?

Last edited by space387; 02-25-2017 at 09:38 PM.
Old 02-26-2017, 12:17 AM
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Originally Posted by space387

Where is the emoticon for runaway thread?

Last edited by hrcslam; 02-26-2017 at 01:54 PM.
Old 02-26-2017, 09:42 AM
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Hi HRC, I agree with your observations.

The first agreement IS fuel delivery.
MY test is to FILL a Gallon bottle, check for air/delivery volume.
The method is to safely disconnect the fuel rail feed line then fill the container.

The second agreement is UEGO/EGO sensor requirement.
My experience is DIRECT NTK interface starting in 1984.
MY work was to create the FIRST four EGO for NTK
MY method was the measure with the NTK UEGO/three wire EGO, same pipe, same time, bench dyno test.
WHAT WAS FOUND :
BOTH sensors read accurately when in the intended AFR/Operating Range.
The tested three wire EGO was UPGRADED by fitment of a Signal Ground Wire on the body of the sensor base with a hose clamp.
THUS the "birth" of the NOW COMMON four wire "hot start" NTK sensor.

UNDERSTAND that the EGO works (requires) best when the exhaust gas temperature is between 800-1400 F.
The UEGO work (reads) fine over a much greater EGT range.

NOW the MAIN CONCERN is many "Wide Bands" read different in the same pipe, in the same time test.
WORST CASE is the Innovate/NTK test data.
The NTK (most ALL others) will read 13:1 compared to the Innovate read of 12:1.

The "so called" Wide Band UEGO Bible tool is commonly found to be untrue.

Again by bet is on "HRC" as a better tuner.

Lance
Old 02-26-2017, 12:28 PM
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I officially declare this thead hijacked and off topic.
Old 02-26-2017, 12:55 PM
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Did the fuel filter get changed? Cause that WILL act just like a bad pump, and it causes the pump to cavitate which heats the fuel up... I read through twice saw the filter on one list but not if it got installed..
Old 02-27-2017, 12:18 AM
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Not yet. I work 24 hour shifts and this time I'm on for 40 hours so I'll get to it thiso week with a few other filters and oil


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